In the packaging of liquids and carbonated beverages, a commonly used closure and container arrangement is one wherein the container has a crown finish, that is, an annular bead at the upper end thereof. The closures commonly comprise metal caps that are crimped onto the crown finish. More recently, it has been common to provide fine threads on the crown finish which perform the function of permitting the closure to be removed by a twisting action so that the threads provide an axial movement of the closure relative to the container. Where the container is made of glass or plastic, it has been found that the percentage of off ware or containers that cannot be used is rather high. Accordingly, it would be desirable to have a twist-off feature in a closure which does not require the formation of threads on the container. Further, the crimping of the cap requires more complex equipment and it would be desirable to provide a cap that does not require crimping.
Insofar as the applicant is aware, it has not been possible to provide a pilferproof band on crown closures which would indicate that the contents have been tampered with or the seal had been broken.
Accordingly, among the objectives of the present invention are to provide a crown closure and container wherein crimping is not required to apply the closure; wherein it is not necessary that the threads be formed on the container to define or provide a twist-off feature; which provides for venting of the contents where the contents are under pressure; and wherein a pilferproof band is provided.
In accordance with the invention, the crown closure and container comprises a glass container having a crown finish without threads, a closure comprising a rigid plastic outer shell and inner cup-shaped liner. The outer shell comprises a top panel and a peripheral skirt. The liner is made of soft resilient plastic material and comprises a top wall and a peripheral wall. Interengaging cam means are provided between the inner surface of the skirt of the shell and the outer surface of the peripheral wall of the liner such that when the closure is applied to the crown finish by an axial motion of the closure relative to the container, the liner is forced into the shell and the upper portion of the liner engages the crown finish of the container. The peripheral skirt of the outer shell is formed with threads so that the upper portion of the liner is forced into the threads and will allow for sufficient interference with the liner and finish to permit removal of the closure by rotation of the shell in relation to the liner.